View Compilation Error

0_0_33503635_24794.cpp: In function 'void dps(int)':
0_0_33503635_24794.cpp:14:7: error: 'x' was not declared in this scope
  if(f[x]=1)
       ^
0_0_33503635_24794.cpp:16:4: error: 'x' was not declared in this scope
  f[x]=1;
    ^
0_0_33503635_24794.cpp:22:6: error: 'b' was not declared in this scope
  if(!b)
      ^